24 EXPERIMENTS WITE PLANTS 



path of the water to and around the germ and endo- 

 sperm, but not into it. 



In most of the thick covers (Filbert, Walnut, 

 Pecan, Peach, etc.) we shall find that the water pur- 

 sues special paths in the tissue of the cover. These 

 represent the paths which the sap took while the fruit 

 was still attached to the plant. It will prove interest- 

 ing to obtain young fruits of various kinds and place 

 the cut surface of the stem in eosin solution, to trace 

 the path taken by the sap. 



It may prove interesting to raise the question, Is 

 not the seed-cover (in spite of the opening) a serious 

 hindrance in absorbing water? We may answer this 

 by removing the covers from some seeds and placing 

 them in water (together with the untreated seeds for 

 comparison) . Select ten lots of seeds (twelve in each 

 lot) free from cracks, etc. Remove the covers from 

 one lot and then weigh each lot separately. Sub- 

 merge them all in water, keeping the different lots 

 separate. After half an hour remove one of the 

 untreated lots; take off the covers and weigh. Let 

 the covers stand until "air-dry," and then weigh 

 them. Deduct this weight from the original weight 

 of this particular lot; this will give us approximately 

 the original weight of the seed-contents (i. e., the 

 seed minus its covers). We now know approximately 

 how much the seed - contents weighed at the start, 

 also how much they have gained. We may compare 



